The danger in all this is not just a corruption of science but also an emasculation of politics. The key debates about climate change are political, not scientific. How much resource should we put into mitigating emissions and how much into adapting to a warmer world? How do you deal with the fact that slower economic growth may produce less CO2 but may also make it harder for people in developing countries to climb out of poverty? How do we weigh the moral good of cheaper travel with the moral good of reduced emissions? And so on. These are debates about political principles and ethical values that no amount of scientific data can resolve. The trouble is, the more we insist that ‘the science tells us what to do’, the less we are able to engage in the kinds of debates necessary to resolve such issues.